The present invention relates generally to crop harvesting machines, commonly referred to as pivot-tongue windrowers, and, more particularly, to a mechanism to spring load a transport lock for automatically moving a locking pin between locked and unlocked positions.
Pivot-tongue harvesting machines, such as the windrower depicted in U.S. Pat. No. 3,832,837, have been developed to enable the operator to swing the harvester from a transport position rearwardly of the tractor to an outwardly operating position by manipulation of the position of the tongue relative to the frame of the machine. Pivot-tongue windrowers having the pivotable tongue mounted near the center of the harvester, such as seen in U.S. Pat. No. 4,081,946, can be used to harvest crop to either side of the tractor , as well as be transported in a position directly rearwardly of the tractor. Locking devices have been used to lock the harvester in its transport position when being transported from one job location to another.
One such locking device is a pin inserted through appropriately aligned holes in the movable tongue and the stationary frame. This locking pin would then prevent the tongue from moving relative to the frame and, therefore, lock the machine in its transport position. As can be seen in the aforementioned U.S. Pat. No. 4,081,946, the position of the tongue or draw bar relative to the frame is controlled through manipulation of a hydraulic cylinder operatively interconnecting the tongue and the frame; however, because of the desire to control the operating position of the harvester during operation thereof, the controls for the manipulation of the hydraulic cylinder are generally located on the tractor.
Since the two holes corresponding to the tongue and the frame, respectively, must be aligned before the locking pin can be inserted, the procedure for locking the harvester in its transport position can be both frustrating and time-consuming if undertaken by only one person due to the numerous trips between the tractor and the rear of the harvester that may be necessary to assure proper alignment of the holes. Conversely, the withdrawal of the locking pin also requires proper alignment of the corresponding holes, as a slight misalignment may bind the locking pin and make withdrawal thereof difficult.
Having observed the transport lock actuator that is the subject matter of copending U.S. patent application Ser. No. 364,951 filed Apr. 2, 1982 in the names of James T. Donovan and E. Graham Webster and having the same Assignee as the present invention, it was felt that a more reliable, better functioning and less expensive actuating mechanism for a transport lock on a pivot-tongue windrower could be developed.